1. Field of the Invention
The present invention relates to bill acceptor technology and more particularly, to a bill position correction method for correcting the position of an inserted bill in a bill acceptor by utilizing the characteristic of step loss of step motor.
2. Description of the Related Art
Following fast development of modern technology, people accelerate their pace of life and demand a better quality of life with more convenience and rapidness. Therefore, various automatic vending machines, automatic teller machines and bill acceptors are used in public places to sell different products or to provide different consumer services without serviceman. These automatic vending machines, automatic teller machines and bill acceptors are highly invited for the advantage of saving much labor and bringing convenience to people. Further, advanced automatic vending machines provide added functions.
However, counterfeit bills made by evil individuals are circulating in the market. To avoid receiving counterfeit bills, a bill acceptor generally provides a bill validator for validating the authenticity and value of an inserted bill before receiving it. Regular bill acceptors are commonly designed for receiving bills of a predetermined width. Further, different kinds of bills have different security features at different locations. An inserted bill must be kept in accurate alignment with the validator of the bill acceptor so that the validator can accurately validate the authenticity and value of the bill. If a bill is obliquely inserted into the bill slot of a bill acceptor, the inserted bill may deviate from accurate alignment with the validator, causing the validator not able to accurate recognize the security features of the bill. When this problem occurs, the bill acceptor will reject the inserted bill. Thus, the user must insert the bill again, causing inconvenience.
Further, many bill position correction designs have been created for use in a bill acceptor for correcting an inserted bill into an accurate alignment position. A known bill position correction design uses a motor to move two mechanical clamping arms at two opposite lateral sides of the bill passage to correct the position of a deviated bill being transferred by transmission roller sets, and sensors to detect a feedback resistance between the bill and the mechanical clamping arms. If the resistance reaches a predetermined value, the mechanical clamping arms are stopped. However, when a bill is inserted into a bill acceptor, the width and insertion direction of the bill are detected and the detected data is transferred to a control circuit for computing, determining the distance the two mechanical clamping arms to be moved by the motor. However, enhancing the accuracy of the movement of the motor-driven mechanical clamping arms complicates the circuit design of the control circuit and the related sensors, increasing the cost.
Therefore, it is desirable to provide a bill position correction means that eliminates the aforesaid problems.